Heretofore devices have existed for the automatic supply of bar stock for a lathe, an automatic lathe and so forth. In one device the bar stock is automatically supplied by pushing it from the rear end after inserting it into a hole in the main spindle by a push rod connected to a counterweight. In a second device the bar stock is automatically supplied by pushing it from the rear end by a hydraulic cylinder. In a third device the bar stock is automatically supplied by a feed finger which is disposed in the hole of the main spindle. Other various methods exist. In the first device in which the push rod is used, the bar stock is always pushed by the push rod from the back so that a compressive force acts on the said bar stock, therefore; in case of a slender bar stock, there is a drawback that precision in cutting is poor because of the occurrence of vibration due to revolution while the bar stock is in the bent condition. In the second device in which a hydraulic cylinder is employed, a hydraulic unit is needed and its cost is very high, and moreover, some restriction exists on the length of the bar stock. In the third device in which the feed finger is employed, there is a drawback that there is some restriction on the largest diameter of the bar stock because it is necessary to provide the feed finger within the hole of the main spindle and the automatic supplying of bar stock of a comparatively large diameter can not be accomplished.